pyrtmidi

pyrtmidi is a Python interface to RtMidi?. It provides real-time midi input and output.

def print_message(midi):
    if midi.isNoteOn():
        print 'ON: ', midi.getMidiNoteName(midi.getNoteNumber()), midi.getVelocity()
    elif midi.isNoteOff():
        print 'OFF:', midi.getMidiNoteName(midi.getNoteNumber())
    elif midi.isController():
        print 'CONTROLLER', midi.getControllerNumber(), midi.getControllerValue()


import rtmidi
midiin = rtmidi.RtMidiIn()

ports = range(midiin.getPortCount())
if ports:
    for i in ports:
        print midiin.getPortName(i)
    midiin.openPort(1)
    while True:
        m = midiin.getMessage(250) # some timeout in ms
        if m != None:
            print_message(m)
else:
    print 'NO MIDI INPUT PORTS!'

Documentation

The API is copied *near* verbatim from the C++ code. Refer to the  RtMidi tutorial, and take into account the following caveats:

RtMidiIn?

getMessage(timeout_ms=None)

• The message argument has been replaced with an optional millisecond timeout value.
• The function will return a MidiMessage? object, or None if no message is available.

setCallback

• This function works just as described in the above docs, and takes a python callable object.
• This method is most useful with a queue.Queue object to communicate between threads.

MidiMessage?

This class has been taken from the juce library, and includes an excellent comprehensive set of midi functions.  please check here for available methods.

Recipes

The pksampler implements a QObject wrapper for rtmidi.RtMidiIn? that emits a 'message()' signal. The original source can be found at /pk/sampler/midi.py. The essential code is follows:

class MidiInput(QThread):
    def __init__(self, devid, parent=None):
        QThread.__init__(self, parent)
        self.device = rtmidi.RtMidiIn()
        self.device.openPort(devid)
        self.running = False

    def run(self):
        self.running = True
        while self.running:
            msg = self.device.getMessage(250)
            if msg:
                self.msg = msg
                self.emit(SIGNAL('message(PyObject *)'), self.msg)
                self.emit(SIGNAL('message()')

midi = MidiInput(1)
def slotMessage(msg):
   print msg
QObject.connect(midi, SIGNAL('message(PyObject *)'), slotMessage)

The following implements a midi echo for all ports, and is taken from /bin/pkechomidi

import sys
import rtmidi
import threading

def print_message(midi, port):
    if midi.isNoteOn():
        print '%s: ON: ' % port, midi.getMidiNoteName(midi.getNoteNumber()), midi.getVelocity()
    elif midi.isNoteOff():
        print '%s: OFF:' % port, midi.getMidiNoteName(midi.getNoteNumber())
    elif midi.isController():
        print '%s: CONTROLLER' % port, midi.getControllerNumber(), midi.getControllerValue()

class Collector(threading.Thread):
    def __init__(self, device, port):
        threading.Thread.__init__(self)
        self.setDaemon(True)
        self.port = port
        self.portName = device.getPortName(port)
        self.device = device
        self.quit = False

    def run(self):
        self.device.openPort(self.port)
        self.device.ignoreTypes(True, False, True)
        while True:
            if self.quit:
                return
            msg = self.device.getMessage()
            if msg:
                print_message(msg, self.portName)


dev = rtmidi.RtMidiIn()
collectors = []
for i in range(dev.getPortCount()):
    device = rtmidi.RtMidiIn()
    print 'OPENING',dev.getPortName(i)
    collector = Collector(device, i)
    collector.start()
    collectors.append(collector)


print 'HIT ENTER TO EXIT'
sys.stdin.read(1)
for c in collectors:
    c.quit = True